1. Field of the Invention
The present invention relates to a magnetic head for recording data on a magnetic recording medium in which portions corresponding to track portions or parts thereof serve as recording areas having a width substantially the same as a track width and in which portions between the recording areas serve as non-recording areas. The invention also relates to a magnetic recording-reproducing apparatus provided with the magnetic recording medium and the magnetic head.
2. Description of the Related Art
A significant improvement in the areal density of conventional magnetic recording media such as hard disks has been achieved by, for example, reducing the size of magnetic particles constituting a recording layer, changing materials, and improving the precision of head processing. Also, magnetic recording media of a perpendicular recording-type are becoming practical. In this type of magnetic recording media, the areal density is improved by providing a recording layer that is to be magnetized in a direction perpendicular to its surface and a soft magnetic layer below the recording layer. Hence, a further improvement in the areal density is expected in the future.
However, problems such as recording of data on an incorrect track portion adjacent to a target track portion and crosstalk during reproduction, which are caused by the limit of head processing and magnetic field broadening, have become apparent. Hence, the improvement of the areal density by conventional improvement techniques has reached its limit.
As the areal density increases, the track width decreases. However, it has been suggested that the magnitude of a magnetic field leaking from a recording head in the cross-track direction is not reduced even when the width of the recording head is reduced along with the reduction in the track width. Therefore, as the areal density increases, a magnetic signal is more likely to be recorded incorrectly on a track portion adjacent to a target recording track portion.
In view of the above, a number of magnetic recording media have been proposed as candidates for a magnetic recording medium capable of realizing a further improvement in the areal density. In such magnetic recording media, portions corresponding to track portions or parts thereof serve as recording areas having a width that is substantially the same as the track width, and portions between the recording areas serve as non-recording areas.
For example, magnetic recording media such as discrete track media and patterned media have been proposed (see for example, Japanese Patent Application Laid-Open No. 2006-048860). In discrete track media, a recording layer is formed in a concavo-convex pattern corresponding to a track pattern, and convex portions of the recording layer are each formed in the shape of a track portion. Hence, the shape of each recording area corresponds to the shape of a track portion. In patterned media, convex portions of a recording layer are each formed in a shape formed by circumferentially dividing up a track portion, and hence the shape of each recording area is the shape formed by circumferentially dividing up a track portion.
Moreover, other magnetic recording media have been proposed in, for example, Japanese Patent Application Laid-Open Nos. 2006-286085 and 2002-359138. Specifically, for example, ion injection treatment or treatment using a reaction gas is performed on portions corresponding to either recording areas or non-recording areas in a recording layer in order to form the non-recording areas in which the saturation magnetization is made to substantially disappear and the recording areas in which the saturation magnetization remains.
It is expected that the presence of non-recording areas between recording areas, as described above, suppresses incorrect recording of information on a track portion adjacent to a target recording track portion, crosstalk between adjacent track portions, and the like.
However, problems such as incorrect recording of magnetic signals on a track portion adjacent to a target recording track portion are affected not only by the configuration of a magnetic recording medium, such as the shape of recording areas formed in track portions, but also by the configuration of a magnetic head. Hence, problems such as incorrect recording of magnetic signals on a track portion adjacent to a target recording track portion may occur even in a magnetic recording medium in which portions corresponding to track portions or parts thereof serve as recording areas and in which portions between the recording areas serve as non-recording areas.